Endless grinding and polishing belt



Feb. 13, 1940. CHERRINGTQN 2,189,754

ENDLESS GRINDING AND POLISHING BELT 'Filed'April 29, 1958 INVEN TOR.

'By QM ATTORNEY Patented Feb. 13, 1940 UNITED STATES P'A 'I'IEINT OFFICE2,189,754 ENDLESS GRINDING AND POLISHING, BELT George n. Cherrin'gton,Pittsburgh, Pa. Application April 29, 1938, Serial Nb. 204,946

This invention relates to improvements --in endless belts andparticularly to that type-used for grinding and polishing sheetmaterial.

As is well known in the'art, belts forg'rinding and polishing sheetmaterial are usuallyof the wide and. endless type and made of papercoated with any suitable abrasive. To produce an evenly and uniformlyground or polished surfaceof the sheet material, these belts are madeout of one piece of paper material with the adjacent ends matchedtogether at a bias or otherwise and then securely united with adhesive.Such belts are generally of considerable width in order to operate overthe full width of the sheetmaterial which is to be ground or polished. 1v

Belts of this kind traverse at a high rate 0 speed and since the same ismade of strong paper and the adjacent ends glued or cemented together,the pressure of the belt exerted against the sheet material must not betoo great in order to avoid tearing of the belt at the joined ends.

The improved construction of the belt made in accordance with thisinvention considerably differs from the belts now in use for thatpurpose and it is therefore one of the main objects of this invention toproduce a wide and endless belt which has no cross-joined ends.

Another object of this invention is to produce a wide and endless beltwhich is built up in spiral fashion of two or more laps of a continuouspiece of exteriorly coated abrasive paper tape.

Still another object of this invention is to produce a wide and endlessbelt which is built up in spiral fashion of two or more laps of acontinuous piece of exteriorly coated abrasive paper tape, the edges ofwhich being scarfed and glued together to form a cylindrical endlessbelt.

Another object of this invention is to produce a grinding or polishingbelt which possesses a greater strength than belts heretoforeconstructed.

Yet another object of the invention is to produce a grinding orpolishing belt which will not cause creeping on the pulleys over whichthe belt is trained.

A further object of the invention is to produce an endless grinding andpolishing belt which is especially adapted for rough grinding at a muchhigher speed than heretofore possible.

A still further object of this invention is to produce an endlesscylindrical grinding and pol-'- ishing belt which will grind or polishthe surface of sheet material more uniformly.

Yet another object of this invention is to produce an endlesscylindrical grinding or polishing belt which has no cross-seams to tear.

With these and other objects in view the invention will be betterunderstood from the 01- lowing detailed description taken in connectionwith the accompanying drawing wherein:

Figure '1 illustrates diagrammatically an endless grinding or polishingbelt trained over a pair of pulleys.

Figure 2 is a top plan view thereof.

I Figure 3 is an enlarged sectional view along line 3-3- in Figure 1.

Figure 4 shows an exaggerated, isometric and sectional view through apaper-tape as used in this invention, coated at the exterior surfacewith an abrasive and polishing agent with both edges scarfed in a manneras shown, the dot and dash lines indicate the original outline of thetape before scarfing.

Figure 5 is a perspective view of a reel of abrasive tape as may be usedin this invention.

Figure 6 is an enlarged sectional view illustrating the method ofjoining the scarfed edges of the abrasive tape in accordance with thisinvention.

Similar reference numbers indicate corresponding parts in all figures.

Referring now to Figure 5 of the drawing, I have shown a continuouspiece of a strong paper tape II wound on a reel l2. This tape is coatedat its exterior surface I3 with an abrasive agent I4, such, forinstance, as particles of sharp grained sand or emery, varied in size togive a fine or coarse surface.

The exterior surface, as well as the under surface I5 of said tape IImay bescarfed at the edges in a manner as indicated by the numerals I6and II respectively and best shown in Figures 3 and 4.

These scarfed edges I6 and I! may be readily scarfed by means of a pairof oppositely located grinding wheels I8 and I9, operating, at thedesired angle of the scarf, along the edges of said I tape I I. Ofcourse, it is obvious that this is only one of many ways ofaccomplishing the desired result.

After the tape II has been properly scarfed by any suitable method, itis wound upon another reel and then finally, in spiral relation, woundabout a pair of spaced drums (not shown) which predetermined the desiredlength of the collapsed and finished belt.

As the scarfed tape II is wound, in spiral fashion, around the drums theadjacent scarfed edges l6 and I1 are glued or cemented together 2. toform an even joint, thus producing a wide belt from a relatively narrowtape.

In Figure 6 there is shown an enlarged sectional view of an edgewisejointed abrasive paper tape in which a slight depression 20 over thejoint 2| remains and which is caused by rollers or other mediums bymeans of which the glued scarfed edges may be pressed together to form atight joint.

The depression 20, of course, exists over and along the entirecontinuous and spiral seam 22 of the finished belt, thus a continuousspiral depression or groove is formed which greatly assists in disposingof the metal and emery dust removed when grinding sheet material withoutclogging up the natural gaps of the abrasive belt.

It will be seen that the herewith described improved abrasive endlessbelt is particularly adaptable as a grinding and polishing medium forsheet metal because it will grind or polish at a much greater speed thanheretofore attained and, since no cross-seam exists the belt cannot tearat the seam as is frequently the case with belts having suchcross-seams.

From the foregoing description taken in connection with the accompanyingdrawing, the construction of the belt and the method of producing thesame will be readily apparent to those skilled in the art to which theinvention appertains, and while describing the principle of operation ofthe invention together with the device which is now considered to be thebest embodiment thereof, it is to be understood that various changes inthe form, proportion and the minor details of construction may beresorted to without departing from the principle or sacrificing any ofthe advantages of the invention as defined in the appended claims.

I claim:

1. In combination with a pair of pulleys spaced from each other, anendless belt for grinding or polishing sheet metal trained about saidpulleys with portions extending between the pulleys, said beltcomprising a narrow elongated strip of thin flexible material providedalong one side edge with an outer beveled face and along its other sideedge with an inner beveled edge, said strip being coiled to providespirally extending belt sections disposed in side by side relation toeach other with their inner beveled edge faces overlapping their outerbeveled edge faces for the full Width thereof and adheringly secured inface to face engagement with each other, the end convolutions of thestrip being tapered to provide the belt with parallel side edges andform a belt of even width throughout its length.

2. In combination with a pair of pulleys spaced from each other, anendless belt for grinding or polishing sheet metal trained about saidpulleys with portions extending between the pulleys, said beltcomprising an elongated strip of flexible material having an innersoarfed edge face along one side edge and an outer scarfed edge facealong its other side edge, said strip being coiled to provideconvolutions disposed in side by side relation to each other to form acomposite belt of predetermined length and width and having their innerscarfed edge faces adheringly secured upon the outer scarfed edge facesin flat face to face engagement therewith, and abrading material uponthe outer face of the belt.

GEORGE H. CI-IERRINGTON.

